Apparatus for regulating temperature of heated air.



Nnr630,682. Patented Aug. 8, I899.

L. F. GJERS &. J. H. HARRISON.

APPARATUS FOR REGULATING TEMPERATURE OF HEATED AIR.

(Application filed May 2, 1898.) (No M de! 2 Sheats$heet I.

J M-Tm In ventora witnesses.

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No. 630,682. Patented Aug. 8, I899.

L. F. GJERS Q. J. H. HARRISON.

APPARATUS FOR REGULATING TEMPERATURE OF HEATED AIR.

(Application filtl May 2, 1898.) (No Model.)

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UNITED STA S PATENT OFFICE.

LAWRENCE FARRAR GJERS AND JOSEPH HUTCHINSON HARRISON, OF MIDDLESBROUGH,ENGLAND.

APPARATUS FOR REGULATING TEMPERATURE OF HEATED AIR.

SPECIFICATION" forming part of Letters Patent No. 630,682, dated August8, 1899. Application filed May 2; 1898. Serial No. 679,518. (No model.)

in Belgium, No. 136,065, dated May 23, 1898,

and in France, No. 278,144, dated May 21, 1898,) of which the followingis a specification.

As is well known, the air-blast of ironsmelting furnaces is usuallyheated by means of reversible regenerative stovessuchas.

Oowpers, Whitwells, Ford & Moncurs,and

others-which are lined with fire-brick 'andprovided internally with openchecker-work of fire-brick arranged so as to leave spaces between andamong the bricks, two or more of these stoves being worked alternatelyin such a way that while one is beingheated by, the combustion of wastegases from the fur-, nace orby other means another having been heated isused for heating the blast which is passed through it on its way to thefurnace.

It is obvious that from the time the blast is directed into a freshlyheated. stove to' the time when it is directed into another stove thetemperature of the saidrblast will gradually.

decrease, and also that when the blast is again directed into anotherfreshly-heated stove its temperature will suddenly rise, the differencein temperaturesoften amounting in practice to from about .to 150centigrade, (150 to 300 Fahrenheit.) i

It is now generally admitted that blastfurnaces work much moreirregularly when regenerative stoves of the kind mentioned are used forheating the blast than when the older cast-iron pipe-stoves are usedthrough which air and hot gasesare separately passed in a continuousmanner and in which the blast is heated to an approximately uniformdegree. Regenerative stoves, however, possess the advantage of beingable to heat the air-blast to a much higher temperature than is possiblewith the older pipe-stove, which results in a reduced fuel consumptionin the furnace. When using regenerative stoves, however, the smeltingmaterials in the blastfurnace very frequently form scaffolds or ledgesof partly-fused material that stick to the sides of the furnace andprevent proper descent of the charge to the hearth or: crucible below.Sometimes very great trouble is experienced in removing such scaffolds.In other cases, on account of the melting and withdrawal of the portionofthe charge below and the increasing weight of the charge above, theobstruction frequently gives way suddenly, thereby causing a rapiddescent of the upper portion of the charge, technically called a slip,into the hearth below. Mean- ,while, the proper working of the furnaceis not only interfered with, but there is little or no gas formed tosupply the steam-genera- 'tors and stoves used to supply and heat theblast with the result that the pressure and temperature of the blastdecreaseat a time when the furnace requires the blast to be at itshighest pressure and temperature; With the old form of pipe-stoves, onthe contrary,

scaffolding and slipping rarely take place.

Investigation has shown that the irregularity in the working ofblast-furnaces when regenerative stoves areused is due to, the variationin the temperature of the blast heated by such stoves. Highertemperature'of the blast produces quicker combustion of the fuel, Withincreased temperature in the vicinity of the twyers, anda consequentlyreduced height of melting zone, so that the partlyfused materials in theregion slightly above the new melting zone stick together and formascaffold, which is likely to be a very objectionable one when a veryhot stove comes into use after a comparatively cold one. a

Now this invention has reference to means or apparatus whereby air orother gas heated by being passed through a regenerative stove or chamberof the kind hereinbefore referred to previously heated by the combustiontherein of gases from a furnace can be maintained at a nearly uniformand high temperature notwithstanding that the temperature of theregenerative stove or chamber through which it is passed and in which itis heated is being gradually reduced. For this purpose there is providedin connection with regenerative stoves or chambers of the kindhereinbefore referred to a heat-equalizer, which is '1; mayadvantageously be of similar construction to an ordinary regenerativestove and through which the heated air orgas is passed after leavingeach of the regenerative heatingstoves in turn and before it reaches theblast or other furnace or place to which it is to be supplied, thearrangement being such that the excess of heat taken up by the air orgas upon passing through a freshly-heated regenerative stove will betransferred to and stored in the heatequalizer to be subsequently givenup to cooler air or gas that has passed through the stove after the samehas been reduced in temperature, so that the air or gas delivered fromthe heat-equalizer to the furnace or other place will be at anapproximately uniform temperature.

Figure 1 of the accompanying drawings illustrates diagrammatically insectional plan an arrangement of combined blast-furnace 1, regenerativeair-heating stoves 2 2 2", and heat-equalizer 3 according to thisinvention. Fig. 2 is a cross-section on the line a: at, Fig. 1.

The heat-equalizer 3 has an inlet4= in communication with a hot-blastmain 5,into which hot air is delivered from each of the regenerativestoves 2 2 2 in turn, which are heated by the combustion therein of hotgases from the blast-furnace, as well understood, the connection betweeneach stove and the main 5 being elfected through a branch pipe 5,controlled by a valve 5.

6 is a blowing-engine by which air is delivered through piping 7alternately to each stove, the connection between each stove and thepiping 7 being effected by a branch pipe '7 with a valve 7 8 is theoutlet of the heat-equalizer in constant communication with thehorseshoe hotblast main 9 of the furnace 1.

10 is a gas-main in constant communication, by means of a main 11, withthe exit for hot gases from the top of the blast-furnace 1, the saidmain 10 being adapted to be placed in communication with each'of theregenerative stoves 2 2 2 by a branch pipe 12, provided with a valve 13.

14 is a main in constant communication with a chimney and also adaptedto be placed in communication with each of the regenerative stoves 2 2 2by means of apipe 15, provided with a valve 16. The arrangement is suchthat by closing the air-valves 5 and 7 and by opening the gas-valves 13and 16 corresponding to any regenerative stove hot gases from theblast-furnace 1 can in a manner well understood be caused to flowthrough such stoves 2 and by their combustion therein with air heat thesame and then pass into the main flue Maud chimney, after which byclosing the gas-valves and opening the airvalves air from theblowing-engine 6 can be caused to pass through the heated regenerativestoves, and thence through the equalizer 3 to the furnace 1.

The heat-equalizer 3 shown is similar in construction to a regenerativestove and comprises an iron shell or casing lined with firebrick andcontaining open fire-brick checkerwork 3. It may consist of a singlechamber or it may be divided Vertically into two or more sections orchambers. In the drawings it is shown divided into two sections by adivision-wall 3 ,such chambers being connected together at the top, sothat when the hot air from one of the stoves 2 2 2" enters at the inlet45 it ascends one chamber and descends the other to the outlet 8 and thehorseshoe hot-blast main 9, and thence to the furnace 1. Vhen the blastpasses from one of the freshlyheated regenerative stoves at its highesttemperature into the heat-equalizer 3, the portion of the checker-workin the latter with which it first comes into contact will be at atemperature corresponding approximately to the reduced temperature ofthe other stove. This blast will consequently give up some of its heatto the heat-equalizer and pass out to the furnace 1 at about a meanbetween the highest and lowest temperatures given by the stoves. \Vhenthe temperature of the regenerative stove through which air for the timebeing is passing and consequently also that of the blast decreases, theheat-equalizer will give up some of its accumulated heat to the blast,which will thus pass out to the furnace with its temperature raised toabout a mean between the highest and lowest temperatures given by thestoves. Thus it will be seen that during the first portion of a stovesrun the heat-equalizer will absorb heat from the blast and during thelatter portion of the run will give up this heat to the blast, afterwhich the blast is directed through another regenerative stove that hasin the meantime been heated, and the same process of absorbing andgiving up heat repeated.

A further advantage gained by the use of a heat-equalizer according tothis invention is that should the furnace work badly from any cause andthere is little or no gas given ofi. therefrom to the stoves thestored-up heat in the heat-equalizer will prevent a sudden decrease inthe temperature of the blast, which would otherwise occur.

It will be obvious that heat-equalizers such as described can also beused with stoves heated by flame and hot gases from specialheating-furnaces instead of by the hot gases from blast-furnaces.

What We claim is ating substantially as hereinbefore described T0 In ahot-blast-furnace plant, the colnbinafor the purposes set forth. tionwith a blast-furnace, air-heating stoves, Signed at2 ExchangePlace,Midd1esbrough and means for causing air and hot gases to on-Tees,England,this 15th day of April, 1898. flow alternately through each ofsaid stoves, LAWRENCE FARRAR GJERS. of a heat-equalizer arranged betweenand in JOSEPH HUTCHINSON HARRISON. communication with the blast-furnaceand Witnesses: stoves and comprising a chamber charged RICHARD HOWSON,with refractory material arranged and oper- GEORGE J OBSON.

